@maurice I just discovered Zavala via your RSS feed. It is exactly the kind of outliner I want. No frills. When outlining pioneer David Dunham's life-changing but now ancient Opal 1.3 (2019) finally dies, I can replace it with Zavala.
Request: Opal has one non-frill feature: Formatting outline items with checkboxes, or (outline-style, nested) numbering. The former allows my outliner to act as a do-list/checklist; the latter allows me to count items easily (I have (1/2)